Lester

Lester is a character who only appeared in rebop for bebop he first appears going to the gang how to make their music better and then slash comes and makes fun of them for having an old man teaching them and then he gets upset and leaves and then they go to find him and he's in a building playing music on his saxophone and then they apologize for what slash says and then he goes with them when they're in the music show and he is presented by fat albert and the gang and he plays music with them.

trivia
he is voiced by Eric Suter who is the voice of Rudy he looks similar to another character uncle Monty who came out in a episode from season 4 called shuttered window and was also voiced by Eric Suter.